Optoelectric integrated device having a three-dimensional solid configuration

ABSTRACT

An optoelectric integrated device includes a three-dimensional solid semiconductor crystal, such as a silicon ball, and a plurality of optical devices including a light-emitting device and a light-receiving device integrated on the surface of the semiconductor crystal. Light is emitted and received between the light-emitting device and the light-receiving device through the interior of the semiconductor crystal used as an optical wiring medium.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optoelectric integrated device inwhich light-emitting and light-receiving devices are arranged on thesurface of a three-dimensional solid semiconductor crystal, such as aball-shaped silicon (Si) substrate (referred to as a Si ball in thisspecification). The optoelectric integrated device is typically anoptoelectric processing unit which is applicable to a neurocomputer andthe like.

2. Related Background Art

One conventional method of rapidly operating a central processing unit(CPU) is to narrow the width of the electric wires used therein and toincrease the integration density. This method is, however, accompaniedwith the pin-bottle-neck problem that the integration density isrestricted by the number of electric wires, which drastically increasesas the number of devices increases. Several methods for solving thisproblem have been proposed as follows.

(1) Optical wiring

This method aims to solve the pin-bottle-neck problem by replacing aportion of the electric wiring by optical wiring. The total number ofelectric wires can be reduced owing to characteristics ofnon-electromagnetic induction and broad band of the optical wiring.However, when the optical wiring is arranged using conventional opticalfiber and semiconductor waveguides, the width of the optical pathbecomes far thicker than that of electric wires. Accordingly, only alimited portion of the electric wiring can be replaced by opticalwiring, and the resultant configuration inevitably lacks flexibility.

The method of an open system (e.g., spatial transmission) has also beenproposed. In this case, high density wiring is possible since the degreeof freedom of the spatial transmission line itself is large. However,the positional alignment between light-emitting and light-receivingdevices is exceedingly complicated, and high density integration is hardto achieve. Thus, the total processing capability becomes smaller thanthe case where only electric wiring is used.

(2) Si ball with integrated circuit (IC) thereon (ball IC)

The use of a Si ball has been proposed as one solution of the aboveproblem, by a structure that uses only electric wiring. The integrationdegree per unit volume increases in inverse proportion to the radius ofthe Si ball since the Si ball uses its spherical surface, whosespatial-use efficiency is larger than that of a conventional planar Sisubstrate. Further, the wiring length decreases, and accordingly theprocessing speed is expected to increase due to the effect ofintegration degree multiplied by the wiring length. This method is,however, not a decisive method from the view point of high speedoperation. The reason therefor is that wire width and wire intervaldecrease as the ball radius decreases, and accordingly adverseinfluences of high resistance and electromagnetic induction noiserapidly increase.

As described in the foregoing, a method for radically solving thepin-bottle-neck problem and achieving a high speed processing unit hasnot yet been proposed at present.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an optoelectricintegrated device, such as a processing unit applicable to ultra-highspeed operation, ultra-parallel processing and the like, which can solvethe above pin-bottle-neck problem, and in which optical devices arearranged on the surface of a three-dimensional solid semiconductorcrystal and the interior of the semiconductor crystal is used as anoptical transmission line.

The present invention is generally directed to an optoelectricintegrated device which includes a three-dimensional solid semiconductorcrystal, and a plurality of optical devices including a light-emittingdevice and a light-receiving device integrated on the surface of thesemiconductor crystal, and in which light is emitted and receivedbetween the light-emitting device and the light-receiving device throughthe interior of the semiconductor crystal used as an optical wiringmedium. The present invention is also generally directed to anoptoelectric integrated device which includes a spherical semiconductor,and at least one of a light-emitting device for emitting signal lightinto the interior of the spherical semiconductor and a light-receivingdevice for receiving signal light transmitted through the interior ofthe spherical semiconductor.

In those structures, the solid semiconductor crystal is typically asilicon (Si) crystal on which electronic devices, such as a field effecttransistor (FET) and a transistor, can be easily formed monolithically.If adaptable, other semiconductor crystal, such as germanium (Ge), canalso be used. The three-dimensional configuration is typically a sphereor ball, but other configurations, such as a cubic one, can also beused. An important feature of the present invention is to construct anoptoelectric integrated device in which the interior of a solidsemiconductor crystal, such as a Si ball, is used as an opticaltransmission line and that an optical device (typically, optical devicesand IC) is integrated on the surface of the semiconductor crystal.

The optical device can include a portion composed of III-VNsemiconductor material, such as GaNAs, GaInNAs, AlNAs, and GaInNAsP, orIV semiconductor material, such as SiGe. In this specification, “III-VNsemiconductor material” indicates III-V compound semiconductor materialthat contains nitrogen (N) as a V material.

On the basis of the above structure, the following more specificstructures are possible.

The optical device can be formed on a buffer layer for lattice matchingwhich is formed on the surface of the semiconductor crystal. The bufferlayer adjusts or compensates for a difference in lattice constantbetween the semiconductor crystal and the optical device to secure acrystal growth having a good performance.

The light-emitting device can be constructed such that it emitsspontaneous emission light or induced emission light into the interiorof the semiconductor crystal. The wavelength of the light is longer thana bandgap wavelength of the semiconductor crystal such that the lightcannot be absorbed by the semiconductor crystal.

The light-emitting device can be constructed such that it emits lightinto the interior of the semiconductor crystal, and one or a pluralityof the light-receiving devices can be arranged such that those receivethe light emitted by the light-emitting device. The light-emittingdevice may also be constructed such that it emits spontaneous-emissionlight or induced-emission light into the exterior of the semiconductorcrystal.

The light-receiving device can be arranged such that it receives lightemitted into the interior of the semiconductor crystal by one or aplurality of the light-emitting devices. The light-receiving device mayalso be arranged such that it receives light from the exterior of thesemiconductor crystal.

The light-emitting devices can include a light-emitting device which canemit light into the interior of the semiconductor crystal toward apredetermined light-receiving device, and a light-emitting device whichcan emit light into the interior of the semiconductor crystal toward aplurality of predetermined light-receiving devices. Thereby, flexiblewiring can be constructed with high integration.

The optical devices and an electronic device can be integrated on thesurface of the semiconductor crystal, and the electronic device has atleast one function of switching on and off the light-emitting device,converting light received by the light-receiving device into an electricsignal, and performing arithmetic and logical operations on the basis ofthe electric signal.

As described above, therefore, the interior of a solid semiconductorcrystal is used as an optical path for optical interconnect.

In a typical structure, the wiring for electric connection is formed onthe surface of a Si ball with one or more IC's thereon (a ball IC), andthe interior of the ball IC is used as an optical interconnect path. Insuch a structure, a light-emitting device formed on the Si ball needs tohave a wavelength band which cannot be absorbed by Si. Further, opticaldevices need to operate in the same environment as Si.

In the preferred embodiments of the present invention, the aboverequirements are typically satisfied by a structure in which thelight-emitting device is composed of III-VN semiconductor material, andthe light-receiving device is composed of III-VN semiconductor materialor SiGe. The III-VN semiconductor material represented byGaN_(x)As_(1−x) lattice-matches to Si when x is approximately equal to0.2. When x is approximately equal to 0.03, an active layer composedthereof can emit light at a wavelength of about 1.3 μm which cannot beabsorbed by Si. Further, highly-efficient light emitting diodes (LED)and surface emitting lasers (such as a vertical cavity surface emittinglaser (VCSEL)) can be constructed since a multi-layer film ofGaNAs/AlNAs can be used as a highly-reflective mirror.

The light-receiving device can also be fabricated by substantially thesame construction. Further, the light-receiving device can be moreeasily fabricated by using Si/Ge. The light-emitting device, such asLEDs, formed on the semiconductor crystal can radiate light into theinterior thereof, and have all the light-receiving devices, such asphotodiodes (PDs), receive the emitted light. Thus, the interior of thesemiconductor crystal can be used as a three-dimensional opticaltransmission path. When a laser diode (LD) with a sharp directivityfactor is used as a light source, light emitted thereby can betransferred to a predetermined light-receiving device.

The light source and the light-receiving device can be controlled by theelectronic circuit arranged nearby. The electronic circuit arranged nearthe light-receiving device can not only convert light into an electricsignal but also include an arithmetic and logic circuit capable ofperforming a desired processing therein. A signal received by thelight-receiving device can be processed by ICs in its neighborhood. Theprocessed result can be transmitted through the electric wiring formedon the surface of the semiconductor crystal, or newly transmitted towardthe interior of the semiconductor crystal as an optical signal. A finalprocessed result can be supplied to the exterior of the semiconductorcrystal as an electric signal or optical signal.

These and other advantages will be more readily understood in connectionwith the following detailed description of the more preferredembodiments in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating the entire structure of a first embodimentof an optoelectric integrated device according to the present invention.

FIG. 2 is a view illustrating the first embodiment at the fabricationstage at which IC and electric wiring are formed on a Si ball.

FIG. 3 is a view illustrating the first embodiment at the fabricationstage at which the Si ball with IC and electric wiring formed thereon iscovered with a nitride layer and a flat portion for forming an opticaldevice thereon is formed by polishing.

FIG. 4 is a cross-sectional view illustrating the flat portion of the Siball in the first embodiment.

FIG. 5 is a cross-sectional view illustrating the first embodiment atthe fabrication stage at which optical devices are fabricated on theflat portion of the Si ball.

FIG. 6 is a cross-sectional view illustrating a light emitting diode(LED) fabricated on the flat portion of the Si ball.

FIG. 7 is a view illustrating the energy band structure of an activelayer in the LED.

FIG. 8 is a cross-sectional view illustrating a second embodiment of thepresent invention at the fabrication stage at which optical devices arefabricated on flat portions of the Si ball for forming an optical devicethereon.

FIG. 9 is a view illustrating 1×1 light emission and reception in thesecond embodiment.

FIG. 10 is a view with a cut-away portion illustrating 1×1 and 1×N lightemission and reception in a third embodiment according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

A first embodiment is directed to an optoelectric integrated device inwhich light emitting diodes (LEDs) and photodiodes (PDs) are arranged ina ball integrated circuit on a Si ball (a ball IC). Active layers ofthose devices are chiefly composed of GaInNAs.

FIG. 1 illustrates the first embodiment. In FIG. 1, optical devices 102,such as a LED and a PD, and electronic devices 103, such as acomplementary metal-oxide semiconductor (CMOS) logic, are formed on aspherical Si ball 101 having a diameter of about 1 mm. Those devices 102and 103 are connected to each other by electric wires 104 of material,such as aluminum (Al), arranged on the surface of the Si ball 101. Lightemitted from LED 102 is transmitted through an optical wiring or path105 in the Si ball 101, and received by the PD 102.

The first embodiment is fabricated in the following manner.

The ball IC can be fabricated by a method identical with that disclosedin a conventional proposal, for example, as follows.

Initially, the Si ball 101 is formed. Particles of polycrystalline Siare put in a pipe with a diameter of 2 mm, and fused. A spherical Sisingle crystal is thus formed. The surface of the Si single crystal isthen polished in a manner similar to that for forming a ball bearing. Atruly-spherical Si single crystal with a diameter of 1 mm is thusobtained.

The Si ball 101 is passed through an integrated circuit (IC) processpipe, and subjected to oxidation and diffusion processes. Patterning isconducted on the processed Si ball 101 by a method disclosed in U.S.Pat. No. 6,097,472, or Japanese Patent Application Laid-Open No.11(1999)-54406, for example. In the former method, a circuit patterncorresponding to a spherical surface of Si spherical material isprepared, and the circuit pattern is entirely exposed on more than halfof the entire sphere. In the latter method, an axis passing through thecenter of a spherical IC is initially determined. While the spherical ICis intermittently rotated about the axis, an exposure region of thespherical IC surface corresponding to the rotation angle is exposedusing a mask corresponding thereto. A Si ball IC is thus completed (seeFIG. 2).

After the process of the Si ball IC is completed, optical devices areformed. The Si ball 101 is entirely covered with a nitride layer 301 orthe like, and flat portions 302 for forming an optical device thereonwith a size of about 10 μm are formed by abrasion and polishing (seeFIG. 3). The Si ball 101 is covered with the nitride layer 301 toprotect the electronic devices 103 and electric wiring 104 during agrowth process of the optical device, and the nitride layer 301 alsoserves as a mask for selective growth. Here, the (111) face and itsequivalent faces 302 (in total, eight faces) are used as illustrated inFIG. 3. FIG. 3 shows a half of the Si ball 101.

If necessary, the entire structure may be covered again with a nitridelayer or the like, and a window is then opened only on a devicefabrication region. In this embodiment, a circular opening is formed,since the selective growth of the optical device proceeds in accordancewith the shape of the opening. FIG. 4 illustrates a cross-section of theSi ball 101, particularly the optical device fabrication region,obtained after such a process.

Crystal growth of the optical device will be described. Such technologyas that disclosed in Japanese Patent Application Laid-Open No.12(2000)-332229 can be used for the crystal growth of the opticaldevice. In this crystal growth technology, a mask for selective growthis formed on a Si wafer with a (100) face, on which the electronicdevice is formed. Then, after a thin layer of a first III-V material(e.g., III-VN material) with a lattice constant different from orapproximately equal to that of Si is grown, multiple thin layers of asecond III-VN material with a lattice constant longer than the firstIII-V material and a third III-VN material with a lattice constantshorter than the first III-V material are laid down on the first III-Vmaterial while strain compensation is achieved. In the meantime, afourth III-VN material crystal with a lattice constant approximatelyequal to that of the first III-V material is selectively grown on themask for selective growth by a growth in a lateral direction. An opticaldevice of compound semiconductor is then formed on the fourth III-VNmaterial crystal.

In the first embodiment, crystal is grown in the following manner. Abuffer layer of GaN_(x)As_(1−x) is laid down only on the face 302equivalent to the (111) face, using gas source molecular beam epitaxy(MBE) or metal organic chemical vapor deposition (MOCVD). Here, thenitrogen (N) mole fraction x is gradually changed from 0.2 to 0 suchthat the buffer layer can be lattice-matched to GaAs. After that, a LEDstructure or VCSEL structure with an active layer of GaInNAs/GaAs isfabricated on the buffer layer. An example of the LED will be described.

In FIG. 5, buffer layer 502, LED 503, pin-PD 504 and electrode pads 507are formed on the Si ball 101. The PD 504 receives light 505, and theLED 503 emits light 506. FIG. 6 illustrates an enlarged view of the LED503.

N-type GaAs/AlAs reflective layer 602 with a reflectivity of 90%,GaInNAs/GaAs single quantum well (SQW) active layer 603, and p-typeGaAs/AlAs reflective layer 604 with a reflectivity of 90% are formed onthe wafer of the buffer layer 502. In this LED, reflective layers 602and 604 are provided to enhance its emission efficiency (i.e., toeffectively take out much light in a desired direction).

FIG. 7 illustrates the energy band structure of the active layer 603which includes a single well layer 701 sandwiched by barrier layers 702.The thickness of a cladding layer 703 is controlled such that the lengthof a cavity is equal to a radiation wavelength. Further, an AlAs layerof the p-type GaAs/AlAs reflective layer 604 is oxidized except for itscentral portion to construct a current confinement layer 605.

After growth of the above layers, positive and negative electrodes 606and 607 are formed. Then, the IC 103 is connected to the electrodes 606and 607 after the nitride layer is removed.

Since the light source of this embodiment is a surface emitting LEDstructure, light is emitted over a substantially whole angle. Aspherical lens can be formed on this structure to enlarge the radiationangle. For example, the LED structure is formed after the (111) face andits equivalent faces are etched to lens shapes (e.g., a concave lensshape).

The light-receiving device can also be fabricated by a method similar tothe above fabrication method of the light source. That is, crystalgrowth of the light-receiving device is conducted after adjustment ofthe lattice matching is achieved by a buffer layer. Those opticaldevices are fabricated at a time by the above selective growth technique(see FIG. 5), but the optical devices can also be separately fabricated.

The operation of the first embodiment will be described. A fundamentaloperation will be described first. In the light-emitting device of thisembodiment, the distributed Bragg reflector (DBR) layers 602 and 604 andthe active layer 603 of GaInNAs/GaAs are used. Therefore, the device canbe driven at an operation current of 0.05 mA and an operation voltage of1.5 V, and hence, the device can be directly driven by a logic signal ofa CMOS circuit that operates at 1.5 V or more. Further, in thelight-receiving device, a sufficient light-receiving sensitivity can beobtained by applying a reverse bias of about 1.5 V thereto.

The surface emitting LED and the surface receiving pin-PD are used, andtherefore, light can be emitted over an entire angle and light from anentire angle can be received. This fact makes it possible to obtain aconstruction in which light from the LED located at any one of the (111)face and its equivalent faces (in total, eight faces) can be received bythe light-receiving devices located at the other seven of those faces.

The flow of signals will be described. In FIG. 1, when an electricsignal from the exterior of the ball IC is input into a processorelement (PE) 103 consisting of CMOS and the like, the relevant operationis performed in the PE 103. Then, its output is supplied to another PE103 through the electric wiring 104 or the optical wiring 105. Theelectric wiring 104 transmits the signal in the same way as an ordinaryIC. In the optical wiring 105, light corresponding to the output fromthe PE 103 is emitted from the light-emitting device 102 into the Siball 101 over a wide angle. The emitted light is received and convertedinto an electric signal by the light-receiving device 102.

The signal transmitted through the electric wiring 104 may control thelight-receiving devices 102 such that light can be received only by adesired light-receiving device. The light-receiving sensitivity of adesired light-receiving device 102 can also be controlled. In the firstembodiment, those operations and data transfer are basically performedin the Si ball 101 and on its surface.

In the first embodiment, electronic devices 103 and optical devices 102are arranged on the Si ball 101, and therefore, those devices 102 and103 can be effectively interconnected without any interference betweenthe electric wiring 104 and the optical wiring 105.

Second Embodiment

A second embodiment is directed to an optoelectric integrated device inwhich VCSELs and PDs are arranged in a ball IC on a Si ball. Activelayers of VCSELs are chiefly composed of GaInNAs, and active layers ofthe PDs are chiefly composed of GaInNAs or SiGe. Those materials are notlattice-matched to GaAs.

FIG. 9 illustrates the second embodiment. The second embodiment isdifferent from the first embodiment in that the lattice constant of abuffer layer 502 is in a range between that of Si and that of GaAs, andVCSELs are used as a light source.

In FIG. 9, surface emitting laser (VCSEL) 801, pin-PD 802 with aring-shaped light-receiving surface, and electrode pads 803 are formedon the buffer layer 502 on a spherical Si ball 101 having a diameter ofabout 1 mm. Light 804 is emitted from the VCSEL 801, and light 805 fromanother VCSEL is received by the pin-PD 802.

The second embodiment is fabricated in the following manner.

The ball IC is fabricated by the same method as that of the firstembodiment. After the process of the Si ball IC is completed, opticaldevices are formed as follows.

The Si ball 101 is entirely covered with a nitride layer or the like,and a flat portion for forming an optical device thereon with a size ofabout 10 μm is formed by abrasion and chemical polishing. Here, the(001) face and its equivalent faces (in total, six faces) are used (seeFIG. 8). As described in the first embodiment, the (111) face and itsequivalent faces can also be used.

If necessary, the entire structure may be again covered with a nitridelayer or the like, and a window is then opened only on an optical-devicefabrication region. As described in the first embodiment, the structureis covered with the nitride layer to protect the electronic device anduse the nitride layer as a mask for selective growth. In the secondembodiment, an opening with a diameter of 5 μm is formed in the nitridelayer.

Crystal growth of the optical device will be described. The buffer layer502 of GaN_(x)As_(1−x) is laid down only on the face equivalent to the(001) face, using gas source MBE or MOCVD. Here, the nitrogen (N) molefraction x is gradually changed from 0.2 to y (0.2>y>0). In thisembodiment, y=0.05. After that, desired light source(s) andlight-receiving device(s) are fabricated.

An example of the VCSEL will be described by using FIG. 6 again. Asillustrated in FIG. 6, GaNAs buffer layer 502, n-type AlNAs/GaNAsreflective layer 602 with a reflectivity of 99.9%, undoped active layer603, and p-type AlPAs/GaNAs reflective layer 604 of 99.99% are formed onthe Si ball 101. The combination of AlPAs/GaNAs is used in the p-typereflective layer 604 to achieve the lattice matching between thereflective layer 604 and the GaNAs buffer layer 502, increase arefractive-index difference between the layers of AlPAs and GaNAs, andreduce the hetero-barrier in a valence band of the reflective layer 604.Further, the combination of AlNAs/GaNAs is used in the n-type reflectivelayer 602 to achieve the lattice matching between the reflective layer602 and the GaNAs buffer layer 502, and reduce the hetero-barrier in aconduction band of the reflective layer 604. As a result, ahighly-reflective layer can be formed with a small number of layers, andat the same time a series resistance due to the hetero-barrier can bereduced. Thus, VCSEL 801 capable of operating at small current and lowvoltage can be achieved.

The structure of the active layer 603 will be described by using FIG. 7again. The active layer 603 is composed of a single GaInNAs well layer701 with a thickness of 8 nm, a radiation wavelength of 1.35 μm and astrain of −0.5% (tensile strain), and InGaAs barrier layers 702 with athickness of 10 nm and a strain of 0.5% (compressive strain) whichsandwich the well layer 701. The radiation wavelength is set to about1.3 μm. The strain may be controlled when necessary. An important pointis that the active layer 603 is formed of III-VN and III-V semiconductormaterials to obtain the radiation wavelength (e.g., 1.3 μm) longer thana wavelength of Si absorption edge such that the interior of the Si ball101 can be used as an optical transmission line and achieve a largeband-offset in the conduction band such that thermal characteristics ofthe VCSEL can be improved.

After the above crystal growth, positive electrode 606 and negativeelectrode 607 are formed. Then, the ball IC 103 is connected to theelectrodes 606 and 607 after the nitride layer is removed.

The light-receiving device can also be fabricated by a method similar tothe above fabrication method of the light source. Those optical devicescan be fabricated at a time by the above selective growth technique (seeFIG. 9), but the devices can be separately fabricated by the selectivegrowth. FIG. 8 illustrates the latter example.

As described above, the active layer of the VCSEL 801 needs to be formedof III-VN and III-V semiconductor materials such that the interior ofthe Si ball 101 can be used as an optical transmission line, but theactive layer of the light-receiving device 802 may be formed of SiGesuch that light at a 1.3-μm band can be received thereby. When theactive layer of the light-receiving device 802 is formed of SiGe,selective growths for the light source and the light-receiving deviceneed to be separately performed.

The operation of the second embodiment will be described. In the VCSELof this embodiment, the reflective layers and the active layer of III-VNsemiconductor material are used. Therefore, the device can be driven atan operation current of 0.1 mA and an operation voltage of 1.5 V, andhence, the device can be directly driven by a logic signal from a CMOScircuit that operates at 1.5 V or more. Further, in the light-receivingdevice, a sufficient light-receiving sensitivity can be obtained byapplying a reverse bias of about 1.5 V thereto.

In FIG. 1, when an electric signal from the exterior of the ball IC isinput into a processor element (PE) 103 consisting of CMOS and the like,necessary processing is performed in the PE 103. Then, its output issupplied to another PE 103 through the electric wire 104 or optical path105. The electric wire 104 transmits the signal in the same way as anordinary IC. Different from the first embodiment, the opticaldirectivity factor of the laser used in the second embodiment is high,and hence, the signal is transmitted only to a desired light-receivingdevice. For example, an optical signal emitted from the (001) face canbe received only by the light-receiving device 102 on the (00-1) face asillustrated in FIG. 8. Alternatively, an optical signal emitted from the(100) face can be received only by the light-receiving device 102 on the(−100) face. The received signal is processed by the PE nearby, andtransmitted through the electric wire 104 or optical wiring 105. Thus adesired processed result can be finally obtained. In such a manner,electric wiring 104 and optical wiring 105 can be organically connected.

Third Embodiment

A third embodiment is directed to an optoelectric integrated device inwhich a laser diode (LD) and a light emitting diode (LED) are used as alight source. The LED is used as a light source as in the firstembodiment, and the LD is used as a light source as in the secondembodiment. When necessary, both LED and LD can be used as in the thirdembodiment.

FIG. 10 illustrates the third embodiment. In FIG. 10, reference numeral102 a is a light-emitting device for 1×N optical wiring. When theoptical device as described in the first embodiment is used, an outputfrom the PE can be converted into multiple outputs (i.e., fan-out).Reference numeral 102 b is a light-emitting device for 1×1 opticalwiring. When the optical device as described in the second embodiment isused, 1×1 optical wiring can be achieved. In the 1×1 optical wiring,high speed data transfer can be achieved though flexibility of thewiring is somewhat lowered compared to the 1×N optical wiring.

When desired, optical devices having both functions of the devices 102 aand 102 b can be arranged for a single PE. Thus, 1×1 connection and 1×Nconnection are possible in optical wiring, similarly to electric wiring,and totally N×N connection can be readily achieved. Accordingly, dataprocessing speed can be drastically improved.

As described in the foregoing, in an optoelectric integrated device ofthe present invention, a light source and/or a light-receiving device(typically, IC and a plurality of light sources and light-receivingdevices) are arranged on the surface of a solid semiconductor crystal,such as a Si ball, so that the interior of the semiconductor crystal canbe used as a transmission line. Accordingly, wiring density and transfercapacity can be drastically increased.

Further, since the above optical transmission line is flexible and N×Nconnection can be readily achieved, the above-discussed pin-bottle-neckproblem can be solved.

Furthermore, an optical device whose consumption electric power is verysmall can be fabricated, since a light radiation layer of GaAsN seriescan be readily laid down on the Si ball.

While the present invention has been described with respect to what arepresently considered to be the preferred embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments. The present invention is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. An optoelectric integrated device comprising: athree-dimensional solid semiconductor crystal; and a plurality ofoptical devices, including a light-emitting device and a light-receivingdevice, said optical devices being integrated on a surface of saidsemiconductor crystal, wherein light is emitted and received betweensaid light-emitting device and said light-receiving device through aninterior of said semiconductor crystal which is used as optical wiringmedium.
 2. The optoelectric integrated device according to claim 1,further comprising an electronic device, wherein said semiconductorcrystal comprises a silicon (Si) ball, and said electronic device andsaid optical devices are integrated on a surface of said Si ball.
 3. Theoptoelectric integrated device according to claim 2, wherein saidoptical device includes a portion composed of III-VN semiconductormaterial or IV semiconductor material.
 4. The optoelectric integrateddevice according to claim 3, wherein said III-VN semiconductor materialis selected from the group consisting of GaNAs, GaInNAs, AlNAs, andGaInNAsP.
 5. The optoelectric integrated device according to claim 3,wherein said IV semiconductor material is SiGe.
 6. The optoelectricintegrated device according to claim 1, further comprising a bufferlayer for lattice matching which is formed on the surface of saidsemiconductor crystal, wherein said optical devices are formed on saidbuffer layer.
 7. The optoelectric integrated device according to claim1, wherein said light-emitting device is constructed such that it emitsspontaneous emission light or induced emission light into the interiorof said semiconductor crystal, the light having a wavelength longer thana bandgap wavelength of said semiconductor crystal.
 8. The optoelectricintegrated device according to claim 7, wherein at least one saidlight-receiving device is arranged to receive the light emitted by saidlight-emitting device.
 9. The optoelectric integrated device accordingto claim 1, wherein said light-emitting device is constructed such thatit emits spontaneous emission light or induced emission light into anexterior of said semiconductor crystal.
 10. The optoelectric integrateddevice according to claim 1, wherein said light-receiving device isarranged such that it receives light emitted into the interior of saidsemiconductor crystal by one or a plurality of said light-emittingdevices.
 11. The optoelectric integrated device according to claim 1,wherein said light-receiving device is arranged such that it receiveslight from an exterior of said semiconductor crystal.
 12. Theoptoelectric integrated device according to claim 1, wherein saidoptical devices include plural such light-emitting devices andlight-receiving devices, and wherein said light-emitting devices includea light-emitting device which can emit light into the interior of saidsemiconductor crystal toward a predetermined one of said light-receivingdevices, and a light-emitting device which can emit light into theinterior of said semiconductor crystal toward a plurality ofpredetermined ones of said light-receiving devices.
 13. The optoelectricintegrated device according to claim 1, further comprising an electronicdevice formed on the surface of said semiconductor crystal, saidelectronic device having at least one function selected from the groupof switching on and off said light-emitting device, converting lightreceived by said light-receiving device into an electric signal, andperforming at least one arithmetic or logical operation on the basis ofthe electric signal.
 14. An optoelectric integrated device comprising: asilicon (Si) ball; a plurality of optical devices, including alight-emitting device and a light-receiving device, said light-emittingdevice having an oscillation wavelength longer than a bandgap wavelengthof said Si ball; and an electronic device, said electronic device havingat least one function selected from the group of switching on and offsaid light-emitting device, converting light received by saidlight-receiving device into an electric signal, and performing at leastone arithmetic or logical operation on the basis of the electric signal,and said optical devices and said electronic device being integrated ona surface of said Si ball, wherein light is emitted and received betweensaid light-emitting device and said light-receiving device through aninterior of said Si ball which is used as optical wiring medium.
 15. Anoptoelectric integrated device comprising: a spherical semiconductor;and at least one of a light-emitting device for emitting signal lightinto an interior of said spherical semiconductor and a light-receivingdevice for receiving signal light transmitted through the interior ofsaid spherical semiconductor.